1. Field of the Invention
The present invention relates to a heat storage apparatus of a type in which heat energy is taken out from a heat storage material which is electrically heated by a heat exchanging fluid.
2. Description of the Related Art
In recent years, a demand has been increasing that heat is stored using inexpensive power available late at night so that heat energy so stored is taken out for use in supplying hot water and heating rooms during the daytime, and in association with such a demand, there has been a tendency that high-performance heat storage apparatuses are demanded.
A heat-storage type heat exchanger is known as a heat storage apparatus in the related art (for example, in JP-A-11-264683 (paragraph [0012], FIG. 1)).
The related art will be described by reference to FIGS. 1A, 1B in the patent literature No. 1.
FIG. 13 is a drawing incorporated herein to illustrate what is illustrated in FIG. 1B of the patent literature No. 1, in the drawing, reference numeral 4 denotes a phase-changeable material, and reference numeral 3 denotes a fluid flow path. When a medium such as air is allowed to flow into the fluid flow path 3, this medium absorbs heat energy that the phase changeable material 4 possesses.
There is a statement in lines 6 to 7 in paragraph “0012” in the patent literature No. 1 that states, “a number of quadrangular flow paths 3 are formed by ceramic walls 2a.”
FIG. 14 is a drawing incorporated herein to illustrate what is illustrated in FIG. 1A of the patent literature No. 1. It is seen from the drawing that a ceramic honeycomb 2 which constitutes a heat storage element 1 is partitioned in a grid-like fashion and that a multiplicity of quadrangular flow paths 3 and quadrangular phase changeable material accommodation cells for accommodating phase changeable material are provided.
The heat exchanger, in the related art, constituted by the quadrangular flow paths and phase changeable material accommodation cells has the following problems.
1) Since a number of fluid passageways each having a quadrangular shape exist alternately, it is difficult to allow a heat exchanging fluid to flow into all the fluid passageways uniformly, and there happen to be caused locations where the heat exchanging fluid flows in such a large amount that heat exchanging is completed so quickly and, on the contrary, locations where the heat exchanging fluid flows in such a small amount that heat exchanging is not promoted, thereby making it difficult to obtain a high performance as a whole.
2) Since a number of quadrangular heat storage material accommodation cells exist alternately, the volume of each heat storage material accommodation cell becomes small, and therefore, when heat is taken out of the phase changeable heat storage material, an excessively cooling phenomenon is easy to occur, and therefore, a stable output cannot be obtain.
FIG. 15 is a drawing illustrating another problem inherent in the related art and corresponds to a partial view of FIG. 14, in which it is shown that phase changeable materials 4, 4 stored in quadrangular phase changeable material accommodation cells are placed adjacent to quadrangular flow paths 3, 3. In order to store heat using power available late at night so that the heat so stored is taken out as heat energy during the daytime, the following are needed: a material having an electricity conductive characteristic is used for the phase exchangeable material 4; electrode plates 101, 101 for phase changing the phase changeable material 4 are provided in each of the phase changeable material accommodation cell; and a power supply 103 is connected to these electrode plates 101, 101 via lead wires 102, 102.
Namely, the electrode plates 101, 101 are energized from the power supply 103 late at night so as to phase change the phase changeable material 4. During the daytime, energizing by the power supply 103 is halted, and a heat exchanging fluid such as air or water is allowed to flow through the flow path 3 so that heat is absorbed by the heat exchanging fluid to thereby take out heat energy.
However, the lead wire 102 needs to be drawn out from each electrode plate 101, and taking for example a case shown in FIG. 14, since the phase changeable material 4 is accommodated in 16 cells which are partitioned in a 4×4 fashion, 32 lead wires 102, which results from 16×2, need to be drawn out as a whole, and since such a large number of lead wires 102 need to be laid out, the production cost of the apparatus is increased and the feed control becomes difficult.
Namely, since a number of quadrangular heat storage material accommodation cells exist in an alternate fashion, in order to directly heat the heat storage material using Joule heat, electrode plates need to be placed in all the heat storage material accommodation cells and wiring needs to be installed for the electrode plates so placed. The layout of electric wires becomes complex very much, and this increases the number of components involved, as well as the production costs.